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This is the 75W UV bulb I bought (datasheet; page 2 is English.) I use it to cure UV resin.

I suppose the paint on the glass of the bulb is a filter which simply only permits UV light to go through.

What is the filament made of? Does it emit more UV light than a normal bulb or is it the same?

zomega
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    the glass is different from a normal bulb – jsotola Oct 23 '23 at 18:44
  • glow wire ... it's called a filament – jsotola Oct 23 '23 at 23:21
  • @jsotola I used a dictionary but thanks for the correction. – zomega Oct 24 '23 at 08:57
  • @zomega "glow wire" generally refers specifically to the filament used in the glow wire test (defined by IEC 60695-2 among other standards) for connector heat resistance, used to test whether a connector will catch fire when the wire connected to it heats up to the point of glowing red. It does not refer to filaments in general. – Hearth Oct 24 '23 at 12:25
  • Claiming an incandescent 1000 h UV lamp to be energy saving is advanced marketing. – greybeard Oct 24 '23 at 13:20
  • @greybeard 1000h is actually a usual lifetime of a normal (non UV) bulb. It's not short. You can read it on Wikipedia or in Amazon descriptions (see details) https://amzn.eu/d/5w7bhvd – zomega Oct 24 '23 at 16:29

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Typically they have hotter-running tungsten filaments in order to output more light in the UV part of the spectrum, resulting in shorter life such as 500 hours.

That one claims 1000 hours typical life, which is a trade-off between output and life. As you can see (image from Wikipedia) unless the filament runs quite hot you don't get much of the total output in the UV part of the spectrum (like < 400nm):

enter image description here

The glass envelope is likely different as well, to permit better transmission of UV light that would be blocked by a conventional glass. Wood's Glass is one possibility. Higher power UV discharge lamps may use quartz glass.

Spehro Pefhany
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